Set a system property before forking

[Weijun Wang]

On 03/28/2017 10:38 PM, Weijun Wang wrote:
> Hi Aleksey
>
> On 03/28/2017 05:01 PM, Aleksey Shipilev wrote:
>> Hi,
>>
>> On 03/28/2017 08:29 AM, Weijun Wang wrote:
>>> I have a system property that is used by Java in a very early
>>> stage, which means it has to be set on the command line with
>>> -Dx=y instead of inside a program with System.setProperty().
>>>
>>> Now I'd like to write a benchmark to check how different values
>>> of this system property affect performance. I'm now able to
>>> provide the system property on the command line, run the
>>> benchmark multiple times, and compare the results. But is it
>>> possible to set it inside my benchmark with different values for
>>> different @Benchmark methods so I only need to run once? Since
>>> the @Benchmark methods run inside forked JVMs, I assume there is
>>> a way to set the system property before this forking.
>>
>> This is not possible with annotations. This is possible with Java
>> API and adding .jvmArgs(...) to the options.
>
> Great, I'm trying it now.
>
> So I created 2 OptionsBuilder, the 1st one setting the system
> property to value 1 and include(method1), the 2nd one setting value2
> and include(method2). However, it looks each option still runs both
> method1 and method2. The "Forking 1 times using command" line does
> not show the include() argument at all.
>
> Maybe I misunderstood include()? How to filter @Benchmark methods in
> an option?

Oops, my fault. I still keep the include(classname) call (copied from 
line 96 of org.openjdk.jmh.samples.JMHSample_25_API_GA) and it matches 
everything.

Thanks again, I think I'm on the right road now.

--Max

>
> Thanks Max
>
>>
>> -Aleksey
>>